Tiny tiger muskie make history

Gusher — "They are small, but they just made history," Barry Nielsen said as biologist Garn Birchell poured the first bag of about 20 tiger muskie fry into Bullock Reservoir.

The tiny tiger muskie released into Cottonwood, Bullock and Newton reservoirs should grow to this size in just a few weeks.

Utah Division of Wildlife Resources photo

"These are the first tiger muskies bred and hatched in Utah," Nielsen said, "and the first I know of to be raised in the West."

On April 19, Cottonwood and Bullock reservoirs were each stocked with 100 tiger muskie fry. The fry were small—less than one inch long.

The tiger muskie project has been a special opportunity for Nielsen, a hatchery worker at the Lee Kay pond facility in Salt Lake City and his supervisor Randy Harrison, the fish culture coordinator for the Utah Division of Wildlife Resources.

"Tiger muskies are an incredible fish," Nielsen said. "They're a cross between a northern pike and a muskellunge or 'muskie.' They get the best from both parents; tiger muskies are an excellent predator, and they grow extremely fast.

"Anglers love them because they're a thrill to catch. They can grow to 20 or 30 pounds within a few years."

Aquatic biologists like tiger muskie because the fish are skilled predators. Biologists use tiger muskie in waters in Utah where the biologists need to control unwanted populations of carp, white sucker and a few other non-native fish. Because tiger muskie are sterile, the biologists can control their numbers, which prevents the tigers from overrunning a fishery.

Bullock and Cottonwood reservoirs, where the fish were placed, are about five miles north of Gusher in northeastern Utah.

On April 30, another water in Utah that already has tiger muskies in it—Newton Reservoir—received 108 tiny tigers.

Newton is about 13 miles north of Logan.

Biologists decide to raise their own

Until a few years ago, DWR biologists were importing tiger muskies from hatcheries in states near the Great Lakes. "We were one of several Western states that were asking for fish," Harrison said, "so it was difficult to get the number of disease free fish we needed. And, at more than $1 per inch, they're expensive to buy."

To get past those challenges, the DWR decided to start a tiger muskie breeding program in Utah. "A couple of populations of northern pike were available to us right here in Utah," Harrison said, "but we had to import the muskie."

The northern pike came from Yuba Reservoir south of Nephi. The muskie were imported to the state and raised in DWR ponds.

A challenging fish to raise

Harrison said raising and breeding tiger muskie has been an adventure. "It's been a real challenge," he said. "Very little literature is available on how to raise them."

Nielsen said Utah's hatchery managers can raise rainbows and other trout 'in their sleep.' "We're very good at it," Nielsen said. "With trout, we can crowd them into a raceway as long as we have cold, flowing water that has enough oxygen in it. Trout take to commercial foods readily, so we can feed them food right out of the bag. Breeding is also easy as the females have numerous large eggs, and the males produce a fair amount of healthy milt to fertilize the eggs with."

Tiger muskie and their parents, muskie and northern pike, on the other hand, often don't want to cooperate.

"Timing is everything to successful spawning," Harrison said. "Northern pike are the first to spawn in the spring while the muskie spawn about 30 days later. We have a narrow window when we have the eggs and the milt from the two respective species available at the same time to create the cross.

"Also, since tiger muskies are a cross between species, only about 20 percent of the eggs will get fertilized and hatch under the best of conditions."

Once the tiny fry hatch, another challenge arises.

"We would prefer to stock tiger muskies when they're about three inches long," Harrison explained. "However, tiger muskie are an aggressive predator, and they start eating other fish right away. When we place the fry or fingerlings together into a tank or raceway, they eat each other. Also, tigers want live food, so we can't feed them commercial trout foods."

Harrison said the best solution biologists have found so far is to spread the tiger muskie out as much as possible and to keep an abundance of brine shrimp in the tank for them to feed on. "Unfortunately," he said, "our hatchery at Lee Kay is mostly a glorified 'tough shed,' so we don't have enough room for the fish. We can't keep them very long because we need to separate older fry from the smaller ones. That's why we brought fry to stock into Cottonwood and Bullock even though they're roughly the length of a penny."

How will these small fish survive in a lake full of smallmouth bass and other predators?

"We will likely lose quite a few to predation," Nielsen said. "However, we think their odds are likely about the same as trying to raise them in our tanks under crowded conditions. By getting some out now, we will reduce crowding in the hatchery, so hopefully we can raise some of the remaining fish to a larger stocking size."

Tigers grow fast

If all goes well, these small history makers will grow about seven to 10 inches their first year. After the first year, they should grow roughly 10 to 15 inches a year for the next few years.

By the end of their second year, the tiger muskie will be a top predator in Bullock and Cottonwood. By the end of their third or fourth year, they'll be a true trophy for anglers.

For more information about tiger muskies in Bullock and Cottonwood reservoirs, call the DWR's Northeastern Region office at 435-781-9453.